Alwaght - At least six people were killed and 17 wounded by a suicide bomber outside a Shiite mosque in the Pakistani city of Rawalpindi on Friday, Reuters reported .
The attack took place after a large number of people had gathered in the mosque for a religious event .
"The suicide bomber wanted to enter the (mosque), but blew up at the entrance. He had come on a motorcycle. He went up to the entrance after parking his motorcycle," a wounded security guard told Dawn News television from his hospital bed .
There was no immediate claim of responsibility .
Pakistan has been on high alert for attacks since a Dec. 16 massacre at a school in the city of Peshawar in which at least 145 people, mainly children, were killed .
Shiite Muslims make up about a fifth of Pakistan's population of around 180 million. More than 800 Shiites have been killed in attacks since the beginning of 2012, according to Human Rights Watch .
